package org.lex.utils.pool;

import java.util.concurrent.Callable;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;
import java.util.concurrent.ThreadFactory;
import java.util.concurrent.atomic.AtomicInteger;

public class DaemonExecutor {
	private static final ExecutorService pool = Executors.newCachedThreadPool(new DaemonThreadFactory());

	public static ExecutorService getService() {
		return pool;
	}

	public static void execute(Runnable command) {
		pool.execute(command);
	}

	public static <T> Future<T> submit(Callable<T> task) {
		return pool.submit(task);
	}

	private static class DaemonThreadFactory implements ThreadFactory {
		static final AtomicInteger poolNumber = new AtomicInteger(1);
		final ThreadGroup group;
		final AtomicInteger threadNumber = new AtomicInteger(1);
		final String namePrefix;

		public DaemonThreadFactory() {
			SecurityManager s = System.getSecurityManager();
			group = (s != null) ? s.getThreadGroup() : Thread.currentThread().getThreadGroup();
			namePrefix = "pool-" + poolNumber.getAndIncrement() + "-thread-";
		}

		public Thread newThread(Runnable r) {
			Thread t = new Thread(group, r, namePrefix + threadNumber.getAndIncrement(), 0);
			if (false == t.isDaemon())
				t.setDaemon(true);
			if (t.getPriority() != Thread.NORM_PRIORITY)
				t.setPriority(Thread.NORM_PRIORITY);
			return t;
		}
	}
}
